CVE-2017-3737

openssl: Read/write after SSL object in error state

Published Dec 7, 2017 CVSS 3.0 · 5.9 Medium EPSS 78.7% KEV · Not listed
Description
OpenSSL 1.0.2 (starting from version 1.0.2b) introduced an "error state" mechanism. The intent was that if a fatal error occurred during a handshake then OpenSSL would move into the error state and would immediately fail if you attempted to continue the handshake. This works as designed for the explicit handshake functions (SSL_do_handshake(), SSL_accept() and SSL_connect()), however due to a bug it does not work correctly if SSL_read() or SSL_write() is called directly. In that scenario, if the handshake fails then a fatal error will be returned in the initial function call. If SSL_read()/SSL_write() is subsequently called by the application for the same SSL object then it will succeed and the data is passed without being decrypted/encrypted directly from the SSL/TLS record layer. In order to exploit this issue an application bug would have to be present that resulted in a call to SSL_read()/SSL_write() being issued after having already received a fatal error. OpenSSL version 1.0.2b-1.0.2m are affected. Fixed in OpenSSL 1.0.2n. OpenSSL 1.1.0 is not affected.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Debian DSA Debian DSA DSA-4065-1 openssl1.0 security update
Ubuntu USN Ubuntu USN USN-3512-1 OpenSSL vulnerabilities
History
Type Values Removed Values Added
Metrics epss

{'score': 0.33137}

epss

{'score': 0.417}

Weaknesses

Sources

Status
PUBLISHED
Assigner
openssl
Published
Updated
Sep 17, 2024, 3:53 AM
Reserved
Dec 16, 2016, 12:00 AM
Status
Modified
Published
Dec 7, 2017, 4:29 PM
Modified
Jun 17, 2026, 1:18 AM
Severity
Moderate
Public date
Dec 7, 2017, 12:00 AM